Apparatus for spinning synthetic filaments and fibers of increased bulk and stiffness



Feb. 19, 1963 n. w. RAYNOLDS' ETAL 3,077,633

APPARATUS FOR SPINNING SYNTHETIC FILAMENTS AND FIBERS OF INCREASED BULKAND STIFFNESS 5 Sheets-Sheet 1 Filed May 15, 1958 Figl gavidg na 001d?ran ernaibg ArflzllrSCSmifh/ ATTORNEYS 19, 1963 D. w. RAYNOLDS ETAL3,077,533

THETIC FILAMENTS AND APPARATUS FOR SPINNING SYN FIBERS OF INCREASED BULKAND STIFFNESS Filed May 15, 1958 5 Sheets-Sheet 2 SECTION OFSPIN/VERETTE 8H0 W/NG 9 ONE OR/F/CE T R 1 m R Davld WRaynoldsFrankWAberanihy Arthur S. Smiih ATTORNEYS Feb. 19, 1963 D. w. RAYNOLDSETAL. 3,077,633

G SYNTHETIC FILAMENTS AND APPARATUS FOR SPINNIN FIBERS 0F INCREASED BULKAND STIFFNESS 5 Sheets-Sheet 3 Filed May 15, 1958 I. m. F

DavidWRaynolds Fran/cw Arthur biSmzth INVENTORS AT TORNm 19, 1963 D. w.RAYNOLDS ETAL 3,077,633

APPARATUS FOR SPINNING SYNTHETIC FILAMENTS AND FIBERS OF INCREASED BULKAND STIFFNESS Filed May 15, 1958 5 Sheets-Sheet 4 Fig.13

Figzl5 Davidw Rayn olds FrankWAbernai/zy Arthur S. Smith IN VEN TORS BYXMM ATTORNEW Fig. 17

Feb. 19, 1963 D. w. RAYNOLDS ETA]. 3,077,533

APPARATUS FOR SPINNING SYNTHETIC FILAMENTS AND FIBERS OF INCREASED BULKAND STIFFNESS 5 Sheets-Sheet 5 Filed May 15, 1958 .DaVidWRaynoldsFmnkWAbernat/gl Arthur S. Smil Figzz IN VEN T 0R5 By %@/M ma W ATTORNEYS7,633 j SPINNING SYNTHETIC FILA- APPARATUS ron or INCREASED BULK ANDMENTS AND FEERS 'STIFFNESS David W. Reynolds and Arthur S. Smith,Kingsport, Tenn, and Frank W. Abernathy, New York,fN.Y.,'as'- signersto-Eastman Kodak Company, Rochester, N.Y., 'a corporation of New JerseyFiled May 15, 1958,.Ser.'No. 735,607

6 Claims. (Cl. 18-8) This invention relates to the preparation ofsynthetic filaments and fibers of predetermined cross section and ofpredetermined bulk, stillness, stretch, luster and coveriirg power. Moreparticularly, this invention relates to iinproved dry spinning apparatusfor producing, from cellulose organic acidester spinning solutions,filaments and fibers generally of Y-shaped or modified Y-shapedcross-sections having the aforementioned characteristics.

Heretofore, various processes and apparatus have been provided for theproduction of synthetic filaments and fibers of various cross-sections.Generally these wellknown cross-sections fall within one or twoclassifications such as relatively narrow-and rectangularcross-sections, or round or round-like cross-sections which includefilaments of round and fiat sides, clover-leaf configurations and otherrelated variations produced by physically deforming the filament, afterit has assumed its normal shape, as'it issues from the spinning cabinet.

Typical methods and apparatus for dry spinnin solutions into syntheticfibers are disclosed in US. Patents 2,000,047 and 2,000,048 of May 7,1935, to H. G. Stone. These patents describe methods including theforcing of a heated cellulose ester spinning solution through aspinrierette having a plurality of separated round orifices and into adrying chamber containing an evaporation atmosphere maintained at asuitable drying temperature. By such controlled conditions, filamentscan be 'consistently formed of approximately round or clover-leafcross-section as contrasted to the filaments previously produced ofelliptical shape.

Also, as shown in US. Patent 1,695,455 of December 18, 1928, by drawingthe filaments from the round orifice spinnerette in a direction otherthan perpendicular to the horizontal face of the spinnerette, filamentshaving a more or less flattened cross-section are produced. It is alsoknown that slight variations from the round cross-section can be causedby adjusting the particular evaporating conditions under which thefilaments are dried in the spinning cabinet. A suitable selection ofthese conditions will permit the production, ing round orifices, offilaments with either a smooth or an unsymmetrical irregular surface.

In US. Patent 1,773,969 of August 26, 19-30, the technique of theextrusion of filament forming solutions through circular orifices intoevap-orative atmospheres is also discussed. As described therein it issuggested that the outer layer of the stream of cellulosic materialwhich is initially circular in cross-section as it issues through thespinnerette orifices, hardens or solidifies first forming a skin that istougher and less fluid than the interior. After this initial hardeningof the outer surface, the interior of the filament is precipitated ordried and thereby shrinks while the outer layer is being furtherhardened. The outer shell of the filament being tougher and moredetermined in shape than the interior, the contraction of the volume ofthe interior causes the outer film orlayer to collapse and to assume avery irregular cross-section which is in the form of a figure of manyindentations of varying sizes and shapes and which is often quite fiat.Because of the irregularity of shape and flatness of the cross-sectionof such filaments, their covering power,

from spinnerettes hav-- ate'nt O- 3,077,633 1C6 v Rziiiented Feb. 19, 19

their bulk, stiffness"andfluster are "quite irregular. This Patent1,773,962 then describes the use of "spinnerettes hayingf'orifices ofcompactor squat shape having indenta tion's in'the form of re-entrantangles. The re entrant angles can be constituted by 's-traight'or curvedboundary lines. However, the filaments produced by extrudingcellulose'ester filament'form'in'g solutions through s'uch orifices havemore'orless cross-sections characterized by rounded surfaces.

'As'described in "Hickey Patent j2,373,892 of April 17, l9 45,l-beam'type cross-section filaments or fibers having'a degree ofresilieucy'and crush resistance may be produced by extruding a "suitablecellulose ester "solution through a spinnerette having rectangularorifices, theratio of the length to the width of'each rectangularoIifice being between 1.35 and 1.65. Fibers made from such I-beamfilaments are particularly: useful for manufacturing carpet. materials,as well as, for the manufacture ofruggin'g and other pile fabrics.However, the ends of the -I-'bearn erect a roundshape and do not extendsubstantia-lly above the fiatsection of the I-beam.

An object 'of this invention is the preparation of the desired filamentsand fibers from spinnerette orifices of a-simplified design thatcan'b'eeasily and'accnrately'manufactored.

Yet another object of this invention is to provide spinnerettes havingextrusion orifices of equilateral triangularshapes or 'of'modifiedtriangular shapes.

Other objects will app'ear hereinafter. I g

The features of the inventionincludeemploying equilateral triangular"orifices, non equilateral triangular orifices and modified equilateraltriangular orifices to form cellulose ester spinning solutions intoyarns of novel characteristics I In accordancejwith one feature of thepresent invention these and other objects may be attained by forcing asuitable spinning solution through a spinnerette having a plurality ofequilateral triangular shaped filament forming orifices therein anddrying the resulting filamentsin a spinning cabinet under carefullycontrolled conditions of temperature while subjecting the filaments topredetermined drafting. The temperature of the spinning solution and itsrate of extrusion must "also be controlled for optimum results.

Under the optimum conditions of solution temperature and composition,extrusion, drying and drafting, the wet filaments as they leave theequilateral triangular orifices temporarily assume a triangularcross-sectional shape. However, in accordance with a surprising featureof our invention, by careful control of the extrusion rate, the draftingrate and drying temperatures, there will be a change in the filamentcross-sections from triangular to a Y-shaped cross-section. Underpreferred ranges of operation,-as suggested above, and as described indetail further on'in this specification, the legs of the Y- shapedcross-section filament will length and of substantially uniform shape.Also the angles between adjacent legs of the Y will be substantiallyequal. s

In general the spinnerette having the equilateral triangular orificesmay be employed with any suitable spinning cabinet such' as, forexample, one of the general kind described herein. The Y-shapedcross-section filaments can be prepared in accordance with our inventionwithin a satisfactory range of spinning, drafting and solutionconditions as is described hereinafter.

Another interesting feature of our invention is the discovery thatfilaments produced in accordance with our inventionthrough "equilateraltriangular-orifices have a more perfect Y-shaped cross-section than isobtainable when a spinnerette having Y-shaped cross-section orifices isemployed.

be substantially equal in a,077,eas

As previously stated above, we have found that the Y-shapedcross-section filaments and fibers of our in the three tips of the legsof the V will be greater in di ameter than one taking in the lobes ofthe well-known clover-leaf type of cross-section. This larger circle is,therefore, the effective area of the Y-shaped crosssection and explainsthe increased bulkiness of our novel Y-type of filament and fiber.

While the filaments and fibers extruded from equilateral triangularspinnerette orifices, and further processed in accordance with ourinvention, are preferred for most purposes, We have also discovered thatemploying triangular spinnerette orifices having angles other thanequilateral, the spinning conditions being substantially similar tothose employed with spinnerettes having equilateral triangular orifices,also will give filaments and fibers having bulk and stiffnessmeasurements greater than filaments and fibers extruded from roundorifices, but less than those extruded through equilateral triangularorifices.

We have also found that control of the bulkiness and stifiness of suchfilaments and fibers can be achieved while employing similar spinningconditions by employing, in the spinnerette, orifices which are derivedfrom equilateral triangles. This modified orifice perhaps can be bestdescribed as an equilateral triangle, the corners of which are filled iuand rounded off, the remaining straight sides being of equal length.

The present invention will be further understood by reference to thefollowing detailed description in which several examples of ourinvention are given and to the related drawings in which: n 7

FIGURE 1 is a schematic elevational view, partly in section showing aspinnerette which has equilateral triangular orifices positioned in asuitable dry spinning cabinet which is equipped with suitable auxiliaryapparatus;

FIGURE 2 is a view of the face of a spinnerette showing a plurality offilament forming orifices of equilateral triangular shape;

FIGURE 3 is a greatly enlarged representation of the spinning solutioncoming out of the triangular orifices of the spinnerette and formingfirst into triangular crosssection filaments and then changing into theY-shaped cross-section filaments;

FIGURE 4 is a reproduction of an actual photomicrograph showing thecross-section of several Y-shaped filaments of the present invention;

FIGURE 5 is a reproduction of an actual photomicrograph showing incross-section several regular or cloverleaf filaments made by a priorart method;

FIGURE 6 is a view of a spinnerette face showing a plurality of filamentforming orifices of triangular shape, the angles of each orifice being120, 30 and 30;

FIGURE 7 is a reproduction of an actual photomicrograph showing thecross-section of several modified Y- shaped filaments which were made inaccordance with the invention when employing a spinnerette such as shownin FIG. 6;

- FIGURE 8 is a view of a spinnerette face showing a plurality oftriangular filament-forming orifices each having angles of 24, 78. and78;

FIGURE 9 is a reproduction of an actual photomicro-; graph showing thecross-section of several modified Y-' shaped filaments produced inaccordance with the inven tion through a spirmerette such as shown inFIGURE 8; FIGURE 10 is a view of a spinnerette faceshowing a" onalshape.

plurality of triangular filament-forming orifices each having angles "of78 60 and 42;

FIGURE 11 is a reproduction of an actual photomicrograph showing thecross-section of several modified Y- shaped filaments produced inaccordance with the invention through a spinnerette such as shown inFIG. 10;

FIG. 12 is a view of a spinnerette face showing a plurality oftriangular filament orifices each having angles of 84, 48 and 48;

FIG. 13 is a reproduction of an actual photomicrograph showing thecross-section of several modified Y- shaped filaments produced inaccordance with the inventon through a spinnerette such as shown in FIG.12;

FIG. 14.is a view of a spinnerette face showing a plurality oftriangular filament orifices each having angles of 48, 66 and 66";

FIG; 15 is a reproduction of an actual photomicrograph showing thecross-section of several modified Y- shaped'filaments produced inaccordance with the invention through a spinnerette such as shown inFIG. 14;

v FIGURES 16, 18, and 22 are views of spinnerette faces each having aplurality of orifices of different polyg- These orifices may begenerally considered as being derived from an equilateral triangularorifice whosesides have been reduced respectively by removal of As, 4;,A and A of each side at each corner or, in other words, reducedrespectively to /5, /2 and A of the length. These sides are connected byarcs and the apices of the triangle are filled in above the arc.

FIGURES 17, 19,21 and 23 are reproductions of actual photomicrographsshowing the modified Y-shaped crosssection filaments produced inaccordance with the invention respectively from the spinnerettes ofFIGURES 16, 18, 20 and 2 2.

The details of the operation of our process will be first described inconnection with the production of uniform Y-shaped cross-sectionfilaments through spinnerettes having equilateral triangle orifices.

Referring to FIGURE 1 there is shown schematically a side elevationview, partly in section, of a spinning cabinet 11 and its associatedapparatus by which the novel Y-shaped and modified Y-shaped syntheticfilaments and fibers of the instant invention may be manufactured.

Mounted atthe top of the cabinet is a candle filter unit '12 to which isconnected a spinnerette 13 which in accordance with our invention whenmaking uniformly Y- shaped cross-section filaments has a plurailty oforifices 14 therein which are of the shape of equilateral triangles. Theface of this novel type of spinnerette with the equilateral triangularorifices 14 therein is shown in the greatly enlarged view of FIGURE 2.The candle filter may be uniformly heated by means of heating coils, notshown, which are positioned so as to surround candle filter 12 andthrough which coils may be circulated any appropriate heat exchangemedium such as water maintained at the desired temperature.

Spinning solution of composition described hereinafter is supplied fromconduit 16 through valve 17 to pump 13 which forces the solution at thedesired rate to the candle filter unit 12, thence to spinnerette 13through the equilateral triangular orifices 14 from which it is extrudedinitially in the form of equilateral triangular filaments 25.

The filaments 25 pass downwardly in the cabinet 11 while progressivelylosing solvent by evaporation until, in a substantially solidi edcondition, they leave the cabinet II and pass around godet roll 20,which is positioned below the lower end of the spinning cabinet 11.Godet roll 2i) is driven at auniform speed by means, not shown,

to give the desired draft to the filaments 25. From godet roll 25 thefilaments pass over the usual guide rolls, one of which is shown at 21,and are finally Wound onto a bobbin 22 after an appropriate twist hasbeen imparted thereto, by means not shown.

To -facilitate removal of solvent from the filamen'ts'durmgtheir travelthrough the cabinet, heated air is supplied to the cabinet 11 by meansof-inlet conduits Z3 and 2-4 positioned respectively adjacent the lowerand upper ends thereof, the'air passing through the cabinet and emergesthrough outlet-conduit 26 positioned at asubstantialdistorywhenconsidered in connection with FIGURE *1 of thedrawings and therelated description. Themperatures in the drying cabinets averaging from40 to 90 C. are usable.

stance below spinnerette 13, asillustrated. EXAMPLE 2 5 gf s ff gz gaiz'f igg g gzgzggg; 3 The'cellulose acetate spinning solution of Example 1t th tiesfired Y-cross section sha e is illustrated in Fl was 'Spun intoshaped remiss-section filaments of 75 o p denier per strand using theapparatus and its general URE 3. As shown at 25 the filaments have ustbeen i v operationas pieviously described. The spinnerette had formed bythe triangular orifices and are substantially 1 1 7 19 equilateraltriangular orifices. The conditions of operaof an equilateral triangularcross-section. Further on in tion arm Shown in Table I where they areidentified as the downward progress of the filaments under the con- Notrolled condition of drafting and drying they have changed EXAMPLE 3 tothe desired Y-cross section filaments 25Y' which are p t depictedgreatly magnified'in FIGURE 4. ,5 The cellulose acetate spinningsolution of Example 1 Our process for producing uniform Y-shapedcross-sec- Was spun into Y-S haped cross-Section filaments of 150 tionfilaments is described in further detail in the follow- 'p Strand- Thesplnneret'te had 38 eqllllateral ing examples. angular orifices. Theabove described spinning equipment EXAMPLE 1 was used with the operatingconditionsshown as No. 3 A spinning solution consisting of 26.5%cellulose acem Table EXAMPLE 4 tate, 1.25% titanium dioxide, based onthe weight of the cellulose acetate, 1.75 water and the-remainder beingA difierent spinningsolution consistingof 30.0% ce1luthe solvent,acetone was spun into Y-shaped cross-section 1056 acetate, Water d temamder being acefil'aments of 55 denier using the apparatus and itsgeneral t e o nt as sp n into Y-shaped cross-section filaoperation asdescribed above in connection with FIG- ments of '150 denier per strand.The spinnerette had 7 URE l. The spinnerette had 13 equilateraltriangular equilateral triangular orifices. The above-describedspinorifices therein. The conditions of operation are shown rung q ipmenwas used with the operating conditions in Table I where they areidentified as No. 1. shown as No. 4 in Table I.

Table I Number Ext-ru- Candle Extru- Bottom Top air Bottom Denier offilasion filter sion Top air air inlet air Spin No. per ments speed temptemp., flow, flow, term, inlet nerette Draft strand per meter/ 0. C.cfin. 01m. C. temp, orifice strand min. 0.

55 13 500 e5 e2 500 500 70 85 0. 007 1. 10 75 10 500 62 02 500 500 70 as0. 067 1. 10 150 as 500 65 '61 800 800 70 as 0. 007 1. 10 150 7 211 65500 500 so 90 0.155 1.22 55 500 7 5s 500 s00 s0 s5 0. 047 1. 43 7s 49500 as 500 500 s0 s5 0. 047 i. 43 300 7 100 as 1, 500 1,500 00 90 0.2201.08

In this table the air flow in cubic feet per minute is 4.5 EXAMPLE 5calculated for hundred Stmmmg cabmets The Another spinning solutionconsisting of 26.5% cellud under the i onfice column I?present 01,16lose acetate, 0.6% titanium dioxide pigment, based on of the eflmlateraltnangle' The t g fi f the weight of the cellulose acetate, 1.75% waterand the mfitets minute represents the i atwhmhTh?Sp}nn1ng 50 remainderbeing acetone solvent was spun into Y-shaped soluuqn 9 2 f fi g' fil ifz crosssectionfilaments of denier per strand. The same operation wit tora t ra e ena es am n Spmmng equlpment was employed with the operatingcom change from the initial triangular cross-section to the Y- ditionsShown as 5 in Table L shaped cross-section while properly drying.

Draft may be defined rather broadly as the ratio of the EMMPLE 6 linearvelocity of wind-up of the filaments to the linear 55 A Spinningsolution f the composition Shown in Velocity of extrusion of theSpinning eelution- M ample 5 was spun into Y-shaped cross-sectionfilaments Specifically il il g 5; defined as the rato of the a f f' of75 denier per strand. The same spinning equipment Velocity at W ie t eemeflts are woun Onto an 0 was employed with the operating conditionsshown as the godet roll of a dry spinning cabinet to the calculated inTable 1 average linear velocity at which the quantity of spinningsolution necessary to the formation of any one of the EXAMPLE 7plurality of filaments comprising the bundle offilaments A spinningsolution consisting of 26.5% cellulose wound onto and off the godet rollis extruded through acetate, 1.75% water, the remainder being acetonewas any one of the plurality of orifices in the spinnerette emspun intoY-shaped cross-section filaments of 300 denier ployed in the spinningoperation, the velocities being exper strand. The spinning equipmentherein described was pressed in fth le1 safime units of distant: perunit timg. Folr1 emplfiyed llfiSlllg acspiglnerette fhaving 7equilatfiral tri examp e, i t e aments are woun up att e go et ro anguar ori ces. 0n -tious 0 operation are s own as at the same linearvelocity that the spinning solution is No. 7 in Table I. extruded fromthe spinnerette, the draft is 1.0 thus signi- We have found thatsatisfactory Y-shaped cross-section fying that the linear speed ofwind-up is of the 7 filaments can be prepared under a satisfactory rangeof extrusion speed. Similarly, if the filaments are wound up orwithdrawn from the'cabinet at the godet roll at a linear speed 50%greater than the speed of extrusion, the draft is 1.5 and so on.

' ther columns of Table I are more 'or less self-explanaspinning andsolution conditions. A primary requisite for optimum Y-shapedcross-section yarn is that the spinning draft should be above 1.0 andpreferably above 1.2. However, somewhat deformed Y-shaped cross-sectionfilaments they be obtained using spinning drafts of 0.7'

to 1.0. But as indicated above, for purposes of attaining uniformity ofcross-section a draft above 1.0 is preferable.

The temperatures listed in Table l are temperatures employed to producea quality product with a particular cellulose ester-acetone solution.These temperatures may vary somewhat. Changes in cellulose estercomposition or changes in cellulose ester to acetone ratios may requiresome changes in these temperatures.

We have also found that our spinning process employing spinneretteshaving equilateral triangular orifices operates very well over a rangeof deniers per filament of 1.5 to 43, although higher denier filamentscan be satisfactorily made by our invention.

That the bulk of the Y-shaped cross-section fiber, because of itsincreased surface area, is greater than the clover-leaf or regularcross-section fiber of equivalent denier is shown clearly in thefollowing Table II where comparisons of equivalent samples of regularand Y- shaped cross-section yarn made from the same spinningcompositions are set forth.

Table II BULK TESTS ON REGULAR AND Y SECTION CONTINUOUS FILAMENT YARNSBulk Specific Percent Yarn factor volume, difierence en. in./lb.

Re ular 55/13/.3 163. 7 34. 5 30. 5 Y 55/l3/.3 214.1 45. 1 Re ular 55 3155. 2 23. 7 37. 3 Y 55/36/.3.. 214. 44. 9 Regular 75/10/ 164. 9 --4. 730. 3 75/ -/.3 213. 8 45. 2 Regular 75/49/.3 .a 153. 0 33. 3 29. 6 Y75/40/.3 205. 43. 2 Regular 150/7/.3 149. 5 31. 5 41. 0 Y 150/7 .3 210.5. 44. 4 Re ular 150/38/ 154. 1 32. 4 36. 8 Y l50/33/.3. 210.4 44.3Reculer 300/7/ 3. 158.0 33. 2 33. 4 300/7/.3 211. 0 44. 3

In Table II the numerical expressions 55/ 13/3 and the like representcontinuous filament yarn in terms of total denier, filament count, andtwist. For example, 55/'13/.3 designates a continuous filament yarnhaving a total denier of 55 made up of 13 filaments and having 0.3 turnper inch of twist. The denier per filament of such a yarn is the totaldenier divided by the number of filaments. In this example 55 divided by13 equals approximately 4 denier per filament.

The data in Table II are determined by a test which we have developed inwhich yarn is wound under a specified tension until it fills a spool ofa known volume. The amount of yarn required to fill this volume isweighed. From this weight the Bulk Factor and Specific Volum'e arecalculated. The Bulk Factor is calculated by the following formula:

(Voltune of spoolxdensity of fibers+weight of yarn to fill spool)l00=bulk factor This formula expresses the bulk as a percentage ratio ofthe space occupied by the yarn to the space which would be occupied bysolid material from which the yarn is made.

The Specific Volume is determined by converting the weight of yarn onthe spool to cubic inches per pound.

The column shown as Percent Difference expresses as a percentage, thepercentage difference between the bulk factor, or the specific volume,in the regular and Y-shaped cross-section yarn. It will be noted that incontinuous filament yarn the Y-shaped cross-section yarn has from 29.6to 41.0% more bulk than regular yarn. This difiereuce can be seenvisually when comparing the skeins from which these data were obtained.

Similar data are shown in Table III relative to staple fiber yarn madefrom regular and Y-shaped cross-section fibers of the same celluloseester composition.

8 Table 111 BULK TESTS ON REGULAR AND Y SECTTON STAPLE FIBERS ln TableIII the staple fiber yarns are designated by their cotton count andtheir ply. For example, 20/1 designates a staple fiber yarn made up or"a single end, which is 205 cotton count. This table also shows thedenier per filament (2 d./f.) etc. and the staple length of the fibers(2") etc., from which the staple yarns are spun. The bulk factor andspecific volume are determined as described above in connection withTable II. It will be evident that with samples of yarn of the samecomposition, denier and length and varying only in crosssection, i.e.between regular and Y section, that the Y section staple has from 37.4to 54.2 more bulk. The luster of the Y-shaped cross-section yarn isappreciably greater than that of the regular or clover-leafcross-section of equivalent denier and composition. Luster is measuredby means of a photo-electric cell. The filaments are wound in a parallelmanner around a fiat piece of cardboard or other similar fiat surface.Light reflected off these panels to the photoelectric cell imparts apotential which is translated into a numerical luster level. Oncomparative tests the clover-leaf panel of filaments record 0.77 voltwhereas the Y-shaped crosssection filaments of the same denier record0.83 volt.

EXAMPLE 8 Staple fibers made from Y-shaped cross-section celluloseacetate yarn were employed as a filling material in a pillow. Because oftheir bulk they were found to be satisfactory for this purpose. Asimilar sized pillow containing the same weight of cellulose acetatestaple fibers of equivalent denier of regular cross-section evidencedless bulk and did not resist matting under pressure.

EXAMPLE 9 Cigarette filters were prepared from Y-shaped crosssectioncellulose acetate fibers. Their interesting bulk and stiffnessproperties permit the construction of filters of interesting design.

EXAMPLE 10 Rugs were prepared from Y-shaped cross-section celluloseacetate fibers alone and with other cellulose acetate fibers, rayon,nylon, wool, etc. The bulk and stiffness properties of the Y-shapedfibers permit the construction of rugs of improved design.

The operation of our process is now described in connection with theproduction of less uniform Y-shaped cross-section filament-s throughspinneret-tes having triangular orifices other than equilateral.

A spinning solution of the composition described in Example 1 was spunthrough the individual spinnerettes which have triangular orifices otherthan equilateral as shown in FIGURES 6, 8, 10, 12 and 14, each of whichwas installed in a separate spinning cabinet like that shown inFIGURE 1. The cross-section of the filaments thus produced are shownrespectively in FIGURES 7, 9, ll, 13 and 15.

The cross-section of the filament shown in FIG. 7 is of a modifiedY-shape having substantially no center leg. Contrasted to thiscross-section that of FIG. 9 has a long center leg which is a littlemore than twice the length of the other two legs which are of similarsize. Thecrosssection of the filament of FIG. 11 is somewhatintermedileg is about the length and size of the other two legs but theangles between the legs are not quite equal.

The spinning conditions and the characteristics of'the resulting fibersare tabulated in Table IV wherethey are compared to fibers spunthrough-spinnerettes having the equilateral triangle orifices. Theincrease in bulk of the fibers'spun through these modifiedtriangularorifices over the prior art fibers shownin FIGURE 5, as wellas the variance in bulk between the fibers produced from the varioustriangular orifices is'also apparent in Table IV.

While these yarns were spun as 150 denier, 7 filament, 0

d./f. they can .be prepared as both filament and staple yarns in all.standard deniers and filament counts.

Yarn was spun from each of the odd triangular-shaped orifices at both 65and 70 C. candle filter temperatures. At this particular spinning draft1.25, these yarns would not spin when a candle filter temperature above70C. was employed. The data show that slightly increased stretch valueswere obtained by employing the 70 C. extrusion temperature. Data alsoshow that yarns obtained from the odd triangular orifices have lessstrength than those of uniform Y-shaped cross-section obtained from theequilateral triangular orifices. Percent stretch for Nos. 50750 and70753 yarns which have cross-sections very similar to the uniformY-shaped cross-sections yarn was about the same as the latter, whilestretch for the other types of cross-section is about 3% lower.

Although each of the yarns shown in Table IV showed an increase in bulkover the regular cross-section, none showed an improvement in bulk overthe uniform Y- shaped cross-section yarn. Values, however, for Nos.50750 and 50753 were comparable therewith.

Each yarn shown in Table IV was woven as filling yarn for preparing asmall satin fabric. The yarn spun from the 120, 30 triangle showeda'slight scintillating effect. The other types of yarn displayed aboutthe same fabric appearance as that made when employing a spinnerettehaving the equilateral triangle orifices.

10 section filaments through spinnerettes having modified equilateraltriangular orifices.

The cellulose acetate spinning solution of the compositions described inExample 1 was spun through the spinnerettes which have the modifiedtriangular orifices shown in FIGURES 16, 18, '20-and22, each of whichwas installedin a separate spinning cabinet df'thetype shown inFIGURE 1. The cross-sections of 'the'filaments thus produced are shownrespectively in FIGURES 17, 19,21 and 23. In FIGURES .17 and 19 thecross-'sections'nearly resemble one another. In FIGURE 19 the Y hasbulbs on theends of the legs of the Y. In FIGURE 23 the Y has approachedclover-leaf cross-section and the filament has lost some of the physicalcharacteristicsof the true Y section.

Thespinning conditions and the characteristics of the resulting fibersare tabulated in Table V where they are compared to fibers spun throughthe equilateral triangle orifices as well as the regular fibers of thetype shown in FIGURE 5.

The fraction X shown in connection with FIGURES 16, 18, 20 and 22,i.e.'%, /s, /4 and V3, refers to the length of the sides of theequilateral triangle which is removed from each apex of the triangle inrounding off the 'apicesof the triangle. I

We have found that the rounding of the corners of the'triangular orificecauses the ends of the Y-shaped filament to become rounded and thiseffect becomes greater as more of the corner is removed. As the orificeshape becomes nearly circular, the yarn cross-sections and resemble inappearance the regularcross-section shown in FIGURE 5. Thevyarnsshowsmall increasesin strength and stretch as the ends of the Ybecome more rounded and the shear strength appears to improve slightlyaccording to the twistability and Walker abrasion tests. It appears thatthese changes in Y-shaped cross-sectionfrom the more perfect 'Y-shapedcross-section give not only a slight improvement in strength and stretchbut -a reduction in waste and ply in staple processing. The gain inthisrespect is obtained at the expense of lessening the bulk as isapparent in Table V. It is also apparent that control of the bulk ofthis modified Y-shaped crosssection yarn can be achieved by employingthe modified spinnerette orifices shown in FIGURES 16, 18, 20 and 22.The change in bulk is explained by reference to FIG- Table IV PHYSICALPROPERTIES OF YARNS SPUN FROM VARIOUS TYPES OF 'IRIANGULAR HOLESPINNERETIES No 50741 50741 50744 50744 50747 50747 50750 50750 5075350753 51214 glaudle filter temp, C 65 70 65 70 65 70 65 70 65 Numberholes 7 7 7 7 1 7 7 v 7 7 7 7 l ype (l Equiv. diameter. .110 .110 .110.110 .110 11 110 .115 Degrees in angles -303O 126-30-30 24-78-7878-66-42 78-60-42 84-48-48 84-48-48 48-66-66 48-66-66 60-60- 60 Spin.draft 1. 25 1. 1.25 1.25 1. 25 1.25 1.25 1.25 1. 25 1. 32 Spin. speed,meters/min. 300 300 300 300 300 300 300 300 300 Bottom air temp., 85 8585 85 .85 I 85 85 85 Denier 151 148 147 151 154 149 150 144' Dry, 1. 101.02 1.13 I 1. 14 1.11 1.11 1.10 1.13 1. 20 Dry, percent stretch. 33. 030.0 33.0 36. 4 36. 0 36.2 35. 5 37. 0 36. 8 et 0. 62 0.58 0.61 0. 64.63 63 .63 0. 65 .63 Wet percent stretc 43. 0 39. 4 42. 5 45. 9 45. 748.2 46.0 48.5 45. 6 IPS, gJd 1.30 1. 25 1.27 1. 27 1.28 1.27 1.27 1. 26IPS, percent stretch. 30.0 28.0 30.0 31.8 29. 7 34. 0 31.0 33.2 Luster73 77 77 76 77 78 75 Bulk factor 178.06 184. 53 186. 63 192. 66 196. 78196. 70 Specific volume, cu. in./lb 37. 395 38.75 39. 40. 46 41. 328 41.30 Bulk increase over regular cross-section-appr0x., percent 20 25 26 3033 33 1 Odd triangular. 2 Equilateral triangular.

The operation of our process is now described in con- URES 17, 19, 21and 23 which show the legs of the Y in nection with the production ofmodified Y-shaped cross- 75 various angular relations and of differentshape.

Table V Cross-section Reg. Y 96 X )4 X 34 X Denier/filaments 150 150 150150 150 Jet size 7. l 7. 155A 7. 161A 7. 164A 7. 169A A M X is X M XSpin speed 300 300 300 300 300 Bottom air temp 85 85 85 S5 85 Candlefilter temp 65 65 65 05 65 Draft 1. 0 1.0 1. 0 1.0 1.0 Denier 148 148148 147 146 Elongation, percent stretch:

Sutcr wet 46. 6 45. 6 47. 0 47. 7 4S. 2 Suter dry 37.3 36. 8 38.0 39.038. 7 Suter loop 11. 8 3. 5 5.0 4. 1 4. 7 i Suter knot 18. 4 14.1 15. 517. 0 18. 2 Strength, g./d.:

Sutcr WeiL .63 .63 63 .04 63 Suter dry 1.19 1. 1. 19 1.19 1. 20 Enterloop .80 61 64 62 G7 Suter knot 1. (l 73 77 .77 .93 Walker abresiom. 261 2 2. 5 3. 3 Twistability 42. 5 37. 8 38. 2 40. 6 41. 2 Bulk increase,percent.-. 32. 0 24.0 22. 6 19.0

While particular emphasis has been made to employing cellulose acetatespinning solutions, our process will also operate satisfactorily withother single and mixed organic acid esters such as those containing 2 to4 carbon atoms.

We have noted that yarns composed of Y-shaped crosssection and modifiedY-shaped cross-section filaments are much stiffer and more resilientthan yarns having normal or cloverleaf cross-sections. The effect onstiffness of cross-sectional shape can be estimated by comparing m0-ments of inertia of fibers having different shapes but the samecross-sectional area. By this method we have determined that Y-shapedcross-section filaments are approximately 60% stiffer than regularfilaments of equal size. Furthermore, we have found that when aplurality of Y-shaped cross-section filaments are collected in a bundleas in a yarn strand or in a batting, a greatly increased resilience orstiffness is noted which is more than would be expected from theincrease in stiffness of individual fibers. We attribute this effect tothe interlocking or tongue and groove mingling of the legs of theY-shaped cross-section filaments making up the mass of fibers. Thisinterlocking of fibers causes much greater resistance to inter-fiberslippage than can be obtained in a bundle of normal filaments. Thus theaggregate stiffness of a bundle of Y-shaped cross-section filaments ismuch greater than the sum of the stiffnesses of the individual fibers.

The inherent properties of cellulose acetate fibers of the Y-shapedcross-section described herein are such that they offer numerousdesirable properties in both wovenand knitted fabrics. In such fabricsas ninons, marquisettes, and voiles, the Y-shaped cross-section fibersproduce fabrics having desirable crispness and stiffness which areusually obtained only by special processing techniques or by specialfinishing. In flat fabrics, such as taffetas, twills and satins, theincreased bulk of the Y-shaped crosssection fibers produce fabricshaving greater cover and thickness for a given weight of material. Onthe other hand there is the possibility of using less material toproduce fabrics of the same cover and thickness thereby decreasing thecost. Yarns having a Y-shaped cross-section produce fabrics with lesstendency for the yarns to slip resulting in higher seam strength. Thischaracteristic is particularly important in certain fabrics, forexample,

satins and twills. Loom finished taffetas have a crisper 6 feel whenmade from Y-shaped cross-section yarns.

Knitted fabrics from yarns with Y-shaped cross-sections exhibitincreased body and hand which make them more desirable for certain usessuch as sport shirts, mens ties, and dress goods. Yarns spun from staplefiber of Y- shaped cross-section exhibit increase in bulk and stiffnessas do the filament yarns. In addition, fabrics from these yarns have awool-like feel or hand. In all of the fabrics which have been producedfrom cellulose acetate fibers of the Y-shaped cross-section fabricproperties have been obtained which are desirable and which are notobtained in cellulose acetate fibers of regular cross-section.

Cigarette filters were made from the yarn produced through each of theabove-described spinnerette orifices.

While the filaments produced from the various spinnerette orifices varyin cross-section, the individual filaments from a single spinnerette allhave substantially the same cross-section. The angles between the legsof the Y will be consistently the same or consistently differentdepending on the particular spinnerette employed.

This is a continuation-in-part of our copending application Serial No.476,142 filed December 20, 1954, and entitled Process and Apparatus forSpinning Synthetic Filaments and Fibers of Increased Bulk and Stiffnessand Products Produced Therefrom.

We claim:

1. A spinnerette having filament forming orifices in the form ofequilateral triangles Whose apices have been rounded off to arcs ofequal radii.

2. A spinnerette having filament forming orifices in the form ofequilateral triangles whose apices have been rounded off to arcs havinga common center.

3. A spinnerette having filament forming orifices in the form ofequilateral triangles whose apices have been rounded off to arcs ofequal radii and whose sides have been thus reduced to /s of theirlength.

4. A spinnerette having filament forming orifices in the form ofequilateral triangles whose apices have been rounded off to arcs ofequal radii and whose sides have been thus reduced to /2 of theirlength.

5. A spinnerette having filament forming orifices in the form ofequilateral triangles whose apices have been rounded off to arcs ofequal radii and whose sides have been thus reduced to /s of theirlength.

6. A spinnerette having filament forming orifices in the form ofequilateral triangles whose apices have been rounded off to arcs ofequal radii and whose sides have been thus reduced to of their length.

References Cited in the file of this patent UNITED STATES PATENTS414,090 Taylor Oct. 29, 1889 1,773,969 Dreyfus Aug. 26, 1930 2,013,688Kinsella Sept. 10, 1935 2,588,584 Small Mar. 11, 1952 2,673,368 DenyesMar. 30, 1954 2,804,645 Wilfong Sept. 3, 1957 2,816,349 Pamm et al. Dec.17, 1957 2,825,120 Smith Mar. 4, 1958 2,829,027 'Rayno1ds et al. Apr. 1,1958 OTHER REFERENCES Ki f g, H. W., et 211.: Hydraulics, 5th Ed., Wiley& Sons, N.Y. (1948), page 124.

Die Kunstseide, vol. 11 (1929), pp. 144-150.

1. A SPINNERETTE HAVING FILAMENT FORMING ORIFICES IN THE FORM OFEQUILATERAL TRIANGLES WHOSE APICES HAVE BEEN ROUNDED OFF TO ARCS OFEQUAL RADII.